1. Technical Field The present invention relates to a method of forming a mold, a forming apparatus thereof, a method of manufacturing a plastic lens, and a manufacturing apparatus thereof.
2. Related Art
As a manufacturing apparatus for a plastic lens such as glasses, there is known a device including: a washing device for washing a first mold for forming a convex surface of a lens and a second mold for forming a concave surface of a lens; a forming apparatus for a mold for arranging the first molding die and the second molding die, which have been washed with the washing device, so that the first molding die and the second molding die oppose each other with a predetermined distance therebetween, and for winding an adhesive tape around peripheral surfaces of those molding dies; and a resin injection device for injecting a resin material into a cavity of the mold formed by the forming apparatus, which is formed by the tape, the first molding die, and the second molding die.
For injecting the resin material into the mold, an injection port through which the nozzle can be inserted and through which air is let out of the mold when the resin material is injected through the nozzle is necessary.
Up to now, the injection port is formed by blowing heat-compressed air to the tape wound around the peripheral surfaces of the pair of molding dies as disclosed in JP 09-85754 A.
In JP 09-85754 A, a circular injection port is formed by arranging a heat-compressed air ejecting tube at a predetermined position opposing the tape wound around the peripheral surfaces of the pair of molding dies, and blowing the heat-compressed air against the tape from an end opening of the ejection tube.
When the injection port is formed on the tape by the forming apparatus for a mold, the resin injection device is activated. First, the nozzle is inserted into the injection port and the resin material is filled into the cavity through the nozzle. The injection port needs to be sealed so that the resin material does not leak from the injection port after the resin material is filled in the cavity.
Up to now, the injection port is sealed by irradiating ultraviolet rays to cure the resin after an ultraviolet-curable resin is applied to the injection port as disclosed in JP 06-155481 A.
In the example disclosed in JP 09-85754 A, the heat-compressed air is blown against the tape wound around the peripheral surfaces of the pair of molding dies to bore the injection port, so a base material of the tape or a foreign matter of an adhesive or the like blown by the compressed air enters the cavity.
When a plastic lens is manufactured in a state where the foreign matter is in the cavity, there is a problem in that appearance of the plastic lens becomes poor, or that yield is reduced.
In the example disclosed in JP 06-155481 A, the injection port is entirely sealed with the ultraviolet-curable resin and is cured by irradiating the ultraviolet rays to the resin in order to seal the injection port. However, the injection port is formed in a large circular shape or in an elliptical annular shape in order that the nozzle can be inserted therethrough and that air within the cavity can be let out, so a large amount of expensive ultraviolet-curable resin is necessary.
Accordingly, in JP 06-155481 A, there is a problem that manufacturing cost for the plastic lens becomes high.